This article presents a comprehensive examination of technical trading rules in the Chinese yuan-based foreign exchange market. The investigation employs daily data spanning seven years for 14 developed and 10 emerging market currencies. The analysis encompasses a vast universe of 41,660 trading rules, representing a significant expansion over the previous studies. The stepwise tests, which was employed to address the data-snooping bias, discover excess profitability in at least half of the developed and emerging currencies, implying the heterogeneous market efficiency across currencies. Our results are robust to sub-sample analysis and different parameter values of the stepwise tests.